Externally activated shape changing device

Abstract

The present invention provides a 4D printed component that uses the photoisomerization stimulus as a method of activation. Other 4D printing methods use heat, moisture, a combination of heat and stress, and the heat from a light source as methods of activation. The present invention takes advantage of 3D printing capability and adds the capability of providing a printable material that dynamically changes shape over time when exposed to an external stimulus. The invention reduces the number of required 3D printed parts to create a moving object. This characteristic reduces the amount of onboard weight of the 3D printed components by reducing the number of parts required to create motion. The present invention removes the need for onboard sensors, processors, motors, power storage, etc. This characteristic will allow for manufacturing of, inter alia, novel medical devices, automated actuators, packaging, smart textiles, etc.

What is claimed is: 
     
       1. A photoactivated shape changing device comprising:
 a first layer including a photoactive poly(siloxane) containing pendant azobenzene group; and 
 a second layer including a polyimide film, the second layer being attached to the first layer, 
 wherein the first layer has a grafting density with the second layer of about 0.84. 
 
     
     
       2. The photoactivated shape changing device according to  claim 1 , wherein the first layer is an active layer and the second layer is a passive layer. 
     
     
       3. The photoactive shape changing device according to  claim 1 , wherein the device has a first shape and, when exposed to UV light, the device transforms into a second shape. 
     
     
       4. The photoactive shape changing device according to  claim 3 , wherein, when the first layer is placed proximate to the light source, the device bends away from the UV light. 
     
     
       5. The photoactive shape changing device according to  claim 4 , wherein, when the first layer is placed distal from the light source, the device bends toward the UV light. 
     
     
       6. The photoactive shape changing device according to  claim 3 , wherein only the UV light is used to change from the first shape to the second shape. 
     
     
       7. The photoactive shape changing device according to  claim 3 , wherein, when the UV light is removed, the device reverts to the first shape. 
     
     
       8. A photoactivated shape changing device comprising:
 a first layer including a photoactive poly(siloxane) containing pendant azobenzene group; and 
 a second layer including a polyimide film, the second layer being attached to the first layer, 
 wherein the device comprises an actuator. 
 
     
     
       9. The photoactive shape changing device according to  claim 8 , wherein the photoactive poly(siloxane) containing pendant azobenzene group comprises polymethylhydrosiloxane-g-(4-methoxy-4′-(hexyloxy)azobenzene). 
     
     
       10. A photoactive shape changing device comprising:
 a photoactive first layer; and 
 a non-photoactive passive second layer attached to the first layer, 
 wherein the first layer has a glass transition temperature of about 26 degrees Celsius. 
 
     
     
       11. The photoactive shape changing device according to  claim 10 , wherein the first layer is only activated by UV light. 
     
     
       12. The photoactive shape changing device according to  claim 11 , wherein the device comprises a first shape in the absence of the UV light and the device converts to a second shape in the presence of the UV light. 
     
     
       13. The photoactive shape changing device according to  claim 12 , wherein, when the UV light is removed, the device reverts to the first shape. 
     
     
       14. The photoactive shape changing device according to  claim 11 , wherein, when the first layer is placed proximate to the UV light, the device forms the second shape. 
     
     
       15. The photoactive shape changing device according to  claim 14 , wherein, when the first layer is placed distal from the UV light, the device forms the second shape. 
     
     
       16. The photoactive shape changing device according to  claim 10 , wherein the second layer comprises a polyimide film. 
     
     
       17. The photoactive shape changing device according to  claim 16 , wherein the first layer comprises a poly(siloxane) containing pendant azobenzene group. 
     
     
       18. The photoactive shape changing device according to  claim 8 ,
 wherein, when the device is in the absence of a UV light, the device has a first shape, when the device is exposed to a UV light, the device converts to a second shape and, when the UV light is removed, the device reverts to the first shape.